A chemical associated with cancer growth has been added to a top selling toothpaste, a new report reveals.

Colgate stands behind the use of triclosan in Colgate Total Toothpaste. The company asserts not only that triclosan is safe, but that it can fight gum disease (for an alternative, see our article about making a better toothpaste yourself).

Colgate Total Toothpaste was approved by the FDA for sale in 1997. A Freedom of Information Act lawsuit filed in 2013 led to the early 2014 release of toxicology reports submitted by Colgate. This reports reveals that the company itself sponsored the studies that proved the safety of the chemical.

The reports shows there were concerns regarding triclosan and cancer, but Colgate assured the FDA that triclosan only caused problems at doses much higher than the amount used in their product.

There was evidence of potential problems with triclosan, such as premature birth and bone malformations in lab animals. This evidence, taken in conjunction with more recent research, show that there are concerns regarding triclosan.

A 2010 study showed that triclosan, the chemical most commonly used in antibacterial products, lowered fertility in mice, while a 2013 study showed it lowered sperm count in rats. A 2003 study by the Centers for Disease Control tested the urine of 2,517 Americans, and found triclosan in 75% of them, including children.

Colgate maintains that the 35-page report does not prove triclosan is harmful to human health, citing 80 studies that have been conducted on 19,000 people.

‘In the nearly 18 years that Colgate Total has been on the market in the U.S., there has been no signal of a safety issue from adverse-event reports,’ spokesman Thomas DiPiazza told Bloomberg and adds that a study in 1997 suggested that triclosan did not present a cancer risk for humans.

Colgate says it does not intend to remove triclosan from Total toothpaste.

The FDA’s website says triclosan is not known to be hazardous to humans, but results of studies done on animals have raised enough of a concern to warrant further research into the chemical. At this time, drug regulators do not intend to reexamine Colgate Total unless new research gives them a reason to.

In May, the state of Minnesota became the first state in the US to pass a law banning the use of triclosan in many products. Avon and Johnson & Johnson have declared their intentions to remove the chemical from their products, and Proctor & Gamble has started marketing Crest toothpaste as triclosan-free. The European Union in 2010 banned triclosan from products used with food.